Solved problem of background service crashing - it is a 'feature' of Android 8 where background services are shutdown when the main activity stops. Solution is to make the service a 'Foreground Service' instead (I think - testing now....)

app/src/main/java/uk/org/openseizuredetector/OsdUtil.java

@@ -49,6 +49,7 @@ import android.content.res.XmlResourceParser;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Environment;
 import android.os.Handler;
 import android.os.IBinder;
@@ -164,7 +165,13 @@ public class OsdUtil {
         Intent sdServerIntent;
         sdServerIntent = new Intent(mContext, SdServer.class);
         sdServerIntent.setData(Uri.parse("Start"));
-        mContext.startService(sdServerIntent);
+        if (Build.VERSION.SDK_INT >= 26) {
+            Log.i(TAG,"Starting Foreground Service (Android 8 and above)");
+            mContext.startForegroundService(sdServerIntent);
+        } else {
+            Log.i(TAG,"Starting Normal Service (Pre-Android 8)");
+            mContext.startService(sdServerIntent);
+        }
     }
 
     /**

app/src/main/java/uk/org/openseizuredetector/SdServer.java

@@ -84,6 +84,7 @@ public class SdServer extends Service implements SdDataReceiver, SdLocationRecei
 
     private NotificationManager mNM;
     private NotificationCompat.Builder mNotificationBuilder;
+    private Notification mNotification;
     private SdWebServer webServer = null;
     private final static String TAG = "SdServer";
     private Timer dataLogTimer = null;
@@ -243,10 +244,16 @@ public class SdServer extends Service implements SdDataReceiver, SdLocationRecei
 
         // Display a notification icon in the status bar of the phone to
         // show the service is running.
-        Log.v(TAG, "showing Notification");
-        mUtil.writeToSysLogFile("SdServer.onStartCommand() - showing Notification");
-        showNotification(0);
-
+        if (Build.VERSION.SDK_INT >= 26) {
+            Log.v(TAG, "showing Notification and calling startForeground (Android 8 and higher)");
+            mUtil.writeToSysLogFile("SdServer.onStartCommand() - showing Notification and calling startForeground (Android 8 and higher)");
+            showNotification(0);
+            startForeground(NOTIFICATION_ID,mNotification);
+        } else {
+            Log.v(TAG, "showing Notification");
+            mUtil.writeToSysLogFile("SdServer.onStartCommand() - showing Notification");
+            showNotification(0);
+        }
         // Record last time we sent an SMS so we can limit rate of SMS
         // sending to one per minute.
         mSMSTime = new Time(Time.getCurrentTimezone());
@@ -375,7 +382,7 @@ public class SdServer extends Service implements SdDataReceiver, SdLocationRecei
         PendingIntent contentIntent =
                 PendingIntent.getActivity(this,
                         0, i, PendingIntent.FLAG_UPDATE_CURRENT);
-        Notification notification = mNotificationBuilder.setContentIntent(contentIntent)
+        mNotification = mNotificationBuilder.setContentIntent(contentIntent)
                 .setSmallIcon(iconId)
                 .setColor(0xff000000)
                 .setTicker("OpenSeizureDetector")
@@ -385,7 +392,7 @@ public class SdServer extends Service implements SdDataReceiver, SdLocationRecei
                 .setOnlyAlertOnce(true)
                 .build();
 
-        mNM.notify(NOTIFICATION_ID, notification);
+        mNM.notify(NOTIFICATION_ID, mNotification);
     }
 
     // Show the main activity on the user's screen.

build.gradle

@@ -6,9 +6,10 @@ buildscript {
             url 'https://maven.google.com/'
             name 'Google'
         }
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.3.0'
     }
 }
 allprojects {

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Dec 26 18:31:40 GMT 2018
+#Mon Jan 14 22:11:00 GMT 2019
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.1-all.zip